Fabricating Information Inside Physical Objects for Imaging in the Terahertz Region

Abstract

The infrastruct fabrication and imaging technique described herein uses digital fabrication techniques to embed information inside objects and THz imaging to later decode this information. Information is encoded in a digital model to create structured transitions between materials. Digital fabrication is used to precisely manufacture the digital model with material transitions enclosed internally. A THz Time-Domain Spectroscopy (TDS) system is used to create a volumetric image of the object interior. The volumetric image is processed to decode the embedded structures into meaningful information.

What is claimed is: 
     
         1 . A computer-implemented process for embedding information in a volumetric tag inside of an object, comprising:
 encoding information in a volumetric tag inside a three dimensional physical object during manufacture of the object; and   reading the encoded information using a terahertz (THz) imaging reader.   
     
     
         2 . The computer-implemented process of  claim 1  wherein the encoded information is read by emitting a pulse of THz radiation, toward the object and measuring the reflected pulse from material interfaces encountered at outer and inner surfaces of the object. 
     
     
         3 . The computer-implemented process of  claim 2  wherein the emitted pulse is a broadband pulse and the entire measured reflected pulse is measured as a waveform. 
     
     
         4 . The computer-implemented process of  claim 1  wherein the terahertz (THz) imaging reader uses Time Domain Spectroscopy (TDS) images of the surface and the interior of the physical object to read the encoded information. 
     
     
         5 . The computer-implemented process of  claim 4  wherein each pixel of a TDSimage comprises a time-domain signal with peaks that indicate reflected energy from both the outer surfaces and the inner surfaces of the physical object. 
     
     
         6 . The computer-implemented process of  claim 5  wherein the entire TDS image forms a volumetric data set that can be used to slice through the object along the depth axis of the object and reveal the three dimensional structure. 
     
     
         7 . The computer-implemented process of  claim 1  wherein the physical object is digitally fabricated. 
     
     
         8 . The computer-implemented process of  claim 1  wherein information is encoded at material transitions of layers of the physical object in order to create the volumetric machine-machine readable tag. 
     
     
         9 . The computer-implemented process of  claim 1  wherein the volumetric tag is used for data storage. 
     
     
         10 . The computer-implemented process of  claim 1  wherein the volumetric tag is used for authentication. 
     
     
         11 . The computer-implemented process of  claim 1  wherein the material used to create the tag is selected based on reflected radiation of the material and the amount of radiation transmitted through the material after attenuation. 
     
     
         12 . A computer-implemented process for creating a volumetric machine-readable tag that is embedded in a three dimensional physical object, comprising:
 encoding information at material transitions of layers of the physical object during manufacture of the object in order to create the volumetric machine-readable tag during fabrication of the object.   
     
     
         13 . The computer-implemented process of  claim 12  wherein layers of materials of different refractive properties are used to create the volumetric machine-readable tag. 
     
     
         14 . The computer-implemented process of  claim 12  wherein a multi-layered spatial gray code pattern is used to encode the information in the volumetric machine-readable tag. 
     
     
         15 . The computer-implemented process of  claim 14  wherein a ray scan configuration is used to read the information on the volumetric machine-readable tag. 
     
     
         16 . The computer-implemented process of  claim 12 , further comprising embedding the volumetric tag in the object in a manner so as to provide information on how the object is positioned and oriented. 
     
     
         17 . The computer-implemented process of  claim 12  further comprising randomly placing tag information under the surface of the object as a unique footprint of the object that can be scanned and matched to a 3D model containing the position of all of the features of the object. 
     
     
         18 . The computer-implemented process of  claim 12  wherein the volumetric tag is a matrix tag that contains layers of digital information encoded as physical bits and is imaged using a volume scan configuration. 
     
     
         19 . The computer-implemented process of  claim 12  wherein the volumetric tag has a three dimensional shape recognizable by a human when scanned. 
     
     
         20 . A system for encoding a machine-readable tag inside of a three dimensional physical object during manufacture of the object, comprising:
 creating a digital model of a three dimensional object;   encoding information inside a volumetric tag inside a three dimensional physical object during manufacture of the object using the digital model.